Control for fuel supply system



May 5, 1959 D. c. BREEDING ET AL CONTROL FOR FUEL SUPPLY SYSTEM Filed Oct. 25, 1956 F'LUX DENSITY NVENTORS DAVID C. BREEDING MELvm C. BARTZ ATTORNEY United States Patent CONTROL-FOR FUEL SUPPLY SYSTEM David C. Breeding, and Melvin C. Bartz, South Bend, Ind, assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation ofDelaware ApplicafibnOctoberZS, 1956, Serial-No. 618,364

8 Claims. (Cl. 123-119) The: present invention" relates. to a control. for fuel. sys

t'ems wherein: the: quantity of fuel supplied. by the; system:to..an-'engine is: variedlas a functionof. the time durationof. opening of a fuel valve or valves. The time duratlOllzOf valve opening is. controlledas a function of an engine:- operating condition. such as ambient temperature, engine temperature, ambient pressure, relative humidity, induction. pressure, exhaust temperature and/or. pressure etc..

Inan. application filedon evendate bearing U.S. Serial No; 618,365in the nameof. Melvin C. Bartz there is dis-- closed and claimed" a magnetic control. for directly en ergizing a solenoid fuel'lvalve toopen the valve. for a com trolled. time duration; source: of power. is: lowand the. solenoid is notproperly matched; to. the: magnetic circuit, the circuit disclosedv in;

Other objects and advantages will be readily apparent.

from the. following; detailed descriptionv taken in connection with theappendeddrawingsin which:

Figure 1' is a diagrammatic view of a control embodying our: invention;

Eigure 2, is a" characteristic curve of certain operating relationship; and

Figure: 3 isa diagrammatic view. of fuel valvemounted inroperative. position inan. internal combustion engine.

Referringnowtothe'drawings, primary, secondary and- In. some installations. where the tertiary circuits respectively designated. 10, 12, and 14V connect a source of power. E. to ground orv reference. po tential.v Therprimary-circuit.10-includes a potentiometer R which variesthemagnitude or intensity ofthe power or magnetomotive force supplied to a primary inductor 16 which is wound on a relatively high retentivity core 18. Primary inductor 16 is: connected. through? appropriate wiring harness to a plurality of segmental contacts 20. which are adapted to be successively engaged by a wiper arm- 22 which is connected to ground or reference potential at 24. Arm. 22 is. mounted on a shaft 26 which is arranged to be rotated asa function of engine s can.

The: secondary circuit: includes. a: secondary: inductor 28 wound on core 18 connected on one side to source of power E and on the other side to a transistor or power amplifier 30 through a base current limiting resistance R In some installations R may be omitted if desired. Power amplifier 30 is connected to each of the solenoids 32 a, b, c, d, e, f, g and h respectively located in electrically actuable fuel control members designated 34 a, b, c, d, e, f, g and h. The number of solenoids or fuel control members may conveniently correspond to the number of combustion chambers in "ice the engine to which thefuel supply system is adapted to? supply fuel. Although it is to be understood that theproportion of fuel control members to combustioncham bers may be increased or decreased as desired. Sole-- noids 32 a, b, c, d, e, f; g and Ii are respectively connected by appropriate wiring harness to'segmental con--- tacts designated 36' a, b; c, d, e; f, g and h which areadapted to be successively engaged by awiper arm 22" for connection to ground or reference potential at 24.- Tra'nsistor' 30 is normally'cut off by voltage divider R R The transistor or power amplifier 30 is rendered: conductive when a properly oriented voltage" pulse or a: voltage pulse of proper polarity is received v from secondary inductor 28';

The tertiary circuit 14 includes source of power E; a tertiary inductor 38 wound on core 18 and\resetcon-' tacts 40 which are adapted for actuation in timed relation' to wiper arm 22 for connecting tertiary inductor 38- to ground or reference potential at 42'.

As. shown in' the characteristic curve of Figure 2 'the tertiary circuit 14 brings the reference flux condition of core 18 to saturation in one direction such as is shown at =saturation flux). The" primary circuitcauses the core to become saturated in the opposite direction shown at The time required for flurr in-core 18 to change from to +415, is-controlled bythe magnitude of the voltageor magnetomotive force in the primary inductor 16. It is also to-be" noted in Figure 2 that when wiper arm 22 breaks contact with a segment 20 and the" current is reduced to zerothat there i'ssubstantially no change in flux" and therefore noundesirable: surge of current in the inductor.

Figure 3 shows a nozzle or' fuel control member 34 installed inthe'induction passage 44' of an internalcom'-- bustion engine 46 having a-' combustion chamber 48; As shown, fuel from the supply tank 50isp1aced under: pressure by pump 52 and is delivered tothe member 34. Fuel supplied to the member 34 in excess of the amount injected. into the engine is returned" to the: supply tankvia restricted conduit 54;

In operation the voltage or. magnetornotive force supe plied to the primary inductors 16; isvaried by potentiomr eter R R, is variable in response: to chaug'esrirrv err-'- gine operating conditions-such as induction passage press sure; ambient pressure, relative humidity, engine tern-1 perature, ambient temperature, exhaust temperature and/or pressure or combinations thereof. The voltage: supplied to primary inductors 16 is sufii'eienti to drive core 18' into saturation: The magnitude of the voltage supplied to primary inductors. 16 varies the time re'quired' for the flux to reach saturation in accordance with that following formula! Et: 2" RAM 10" Where:

B=fihx density A=core area, N'=number of turns In a given installation B; A andiN: are: constant therefore:

K t "E- indicating voltage E and time t to be inversely proportional. Thus when the primary circuit is opened and closed by the wiper arm 22 successively engaging segmental contacts 20 the time required during each energization of the circuit for the flux to build up from a reference condition to a saturated condition is controllable by varying R To provide for a reference con dition in the core, the tertiary circuit is energized in timed relation to the energization of the primary circuit to saturate the core in the opposite direction from the direction of saturation produced by the primary inductor. Therefore, upon each engagement of wiper arm with a segmental contact 20 the build up of flux in core 18 is from a reference condition of saturation to satura' tion in the opposite direction whereby the current induced in the secondary inductor 28 by the primary inductor is always in the same direction so as to produce a properly oriented or polarized voltage pulse for causing transistor or power amplifier 30 to become conductive. The time duration of conductivity of power amplifier 30 -is controlled by the time required for core 18-to be saturated by the primary inductor 16 from a reference core flux condition. Wiper arm 22 through successive engagement with contacts 36a to h completes the circuit to the appropriate solenoid whereby actuation of the fuel control members occurs in timed relation to engine operation.

As may be seen the control of our invention requires relatively few parts and may be assembled in a small, light weight package and is of such a nature as to be extremely rugged and reliable in operation. The control, with little or no adjustment, can be used with a variety of electrically actuable fuel members having a variety of electrical characteristics. While only one embodiment of our invention has been described it will be readily apparent to those skilled inthe art that various changes and arrangements can be made to obtainthe objects of the invention without departing fronrthe spirit thereof. ,-We claim:

. Acontrolfor a fuel system having an electrically actuable fuel control member comprising: a primary inductor, a variable source of power, means for connecting saidsourcewith said primary inductor, a secondary inductor, coupled to said primary inductor, a power am plifier connected to said secondary inductor, and means connecting said amplifier to said member.

T 2. A control for a fuel system for an engine having anielectrically actuable fuel control member comprising: a primary inductor, a variable source of power, a circuit connecting said inductor to said source, means responsive to engine'speed for periodically opening and closing said circuit, a secondary inductor coupled to said primary-inductor, means for controlling the direction of induced current in said secondary inductor, a power amplifier, means connecting said secondary inductor to said amplifier, and means connecting saidamplifier to said member.

Y 3.'A control for a. fuel system having an electrically actuable fuel control member comprising: a core, primary, secondaryand tertiary inductors mounted on said core,,means forperiodically supplying a voltage to said primary inductor sufficient to saturate said core in one direction, means for periodically supplying a magnetornotive force to said tertiary inductors sufiicient to saturate said core in a direction opposite said one direction, means for amplifying the current in said secondary inductor, and means connecting said last mentioned means to said member.

"4. A control for aifuel system having an electrically actuable fuel control member comprising: a core, primary, secondary and tertiary inductors mounted on said core, means for periodically supplying a voltage to said primary inductor suflicient to saturate said core in one direction, means for varying ,the magnitude of said force to vary the time required to saturate said core by said primary inductor, means for periodically supplying a magnetomotive force to said tertiary inductors suflicient to saturate said core in a direction opposite to said one direction, means for amplifying the current in said secondary inductor, and means connecting said last mentioned means to said member. a

5. A control for a fuel system having a plurality of solenoid actuated valves comprising: a primary inductor, a. secondary inductor, means for inducing a current in said second inductor for a controllable time duration, means for orienting the direction of induced current, and means for successively connecting said secondary inductor to said solenoids.

6. A control for a fuel system having a plurality of solenoid actuated valves comprising: a primary inductor,

a secondary inductor, means for inducing a current in said. second inductor for a controllable time duration, means for orienting the direction of induced current, a power amplifier connected to said secondary inductor, and means. for successively connecting said amplifier to said solenoids.

7. A control for a fuel supply system having an electrically actuable fuel control member comprising: a first circuit, a source of power, a primary'inductor in said circuit, means connecting said first circuit to said source,

means for periodically opening and closing said'circuit a second circuit, a secondary inductor coupled to said primary inductor, means for connecting said secondary inductor to said member, a tertiary inductor in said cir-.

cuit, means for periodically opening and closing said tertiary circuit in time relation to said last mentioned means, and means connecting said tertiary circuit to said source of power.

8. A control for a fuel supply system having a plural-- ity of electrically actuable fuel valves comprising: a core, primary, secondary and tertiary inductors mounted on said core, primary, secondary and tertiary circuits respectively connected to said inductors, a source of power connected to each of said circuits, means for periodically opening and closingsaid primary circuit to saturate said tion, a normally non-conducting power amplifier in said tertiary circuit, said amplifier being rendered conductive by the voltage induced in said tertiary inductor by said primary inductor, means connecting said amplifier to said valves, and means for successively connecting said valve to a reference potential in timed relation to said first men tioned means.

References Cited in the file of this patent UNITED STATES PATENTS 2,468,917 Booth May 3, 1949 FOREIGN PATENTS 198,796 Switzerland Oct. 1,1938

971,274 France 'luly 5, 1950 

